1. C ORRELATION B ONUS W ORK Completion = up to 20 points toward Exams

2. P ROCESS Choose a partner or two (no groups larger than 3) Take out a sheet of paper and list first/last names for all group members Questions will be posed and you as a group will develop your answers Vocal and physical responses are required...i.e. no participation, no credit! It’s okay to be wrong!!!! We are all here to learn and review!

3. C ORRELATION S TUDY ? H OW DO YOU KNOW ? 1. What words do you see in the text of a journal article or data set description that allows you to recognize the study as a correlational study?

4. C ORRELATION E XAMPLE We will be looking at a correlation example where we are exploring the relationships between variables. Look at Excel

5. H YPOTHESIS T ESTING Step 1: State the Hypotheses 2. State the null hypothesis to test the correlation between gender and time writing is taught each week. Ho: There is no relationship between gender and time writing is taught each week.

6. H YPOTHESIS T ESTING 3. State the alternative hypothesis to test the correlation between gender and time writing is taught each week. Ha: There is a relationship between gender and time writing is taught each week.

7. H YPOTHESIS T ESTING Step 2: Choose and have Excel compute the appropriate test statistic. 4. When we are conducting a correlation, what is our test statistic? Correlation coefficient

8. H YPOTHESIS T ESTING Step 3: Determine the critical value needed to reject the Null 5. When we are conducting a correlation, what do we need to know in order to locate the critical value from the chart? One or Two Tailed; Threshold Value (.05); and Degrees of Freedom

9. H YPOTHESIS T ESTING 6. How do we know if our study is one-tailed or two tailed? Is our current study one or two tailed? What is our degrees of freedom We look at the hypotheses for directional terms. One = Directional ( greater/less than 0; Two = No Directional Terms Our study is two tailed because there are no directional terms in our hypotheses. df = 321

10. H YPOTHESIS T ESTING 7. Looking at the Critical Value Chart B4, what is the critical value for our study? r critical = 0.1946

11. H YPOTHESIS T ESTING Step 4: Compare the obtained value and the critical value and make a decision 8. What do we need to do to the obtained value before we compare the values? Find the absolute value of the obtained value

12. H YPOTHESIS T ESTING 9. What is the r obtained ? r obtained = - 0.0541 r obtained = [- 0.0541] r obtained = 0.0541

13. H YPOTHESIS T ESTING 10. Compare the obtained and critical value? Which is greater? What is your decision with regards to the null hypothesis? Why? r o = 0.0541 <r c = 0.1946 Fail to reject the null hypothesis B/c the critical value is greater than the obtained value

14. H YPOTHESIS T ESTING Step 5: State the conclusion 11. Based on our decision to fail to reject the null, is the relationship significant? Is p greater/less than the threshold value (.05). How do you know? What direction is the relationship between gender and time? How do you know? no p >.05, because there is not a significant relationship Inverse, because the r o is negative.

15. H YPOTHESIS T ESTING 12. Compute r 2 =and explain how much of the variance (change in y) is explained. r 2 =.003 Less than 1% of the variance is explained (time explained by gender)

16. H YPOTHESIS T ESTING 13. Write up your interpretation statement r (df) = obtained, p ?.05, r 2 = ? r (321) = - 0.054, p <.05, r 2 = 0.003

17. H YPOTHESIS T ESTING 14. State your conclusion like you will for the final project. State something about the decision, the direction, and the significance We fail to reject the null hypothesis because the p value is greater than the threshold alpha. While the relationship between gender and time teaching writing each week is inverse, the relationship is not significant.

18. H YPOTHESIS T ESTING Step 6: If significant, then often the prediction line is useful to state... 15. What is the prediction line (in symbols)? ŷ = a + bx or ŷ = bx + a

19. H YPOTHESIS T ESTING 16. What is the prediction line for our study? ŷ = - 3.784x + 36.498 OR ŷ = 36.498 – 3.784x

20. QUESTIONS???? Fold your work in half Write the last names of the group members on the outside. Turn in as you leave. Final Project due May 1 st, 2pm.